How does energy change during physical processes?

Energy changes during physical processes by being transferred, transformed, or conserved according to the laws of physics.

In any physical process, energy can change forms but the total amount of energy remains constant, as stated by the law of conservation of energy. For example, when you boil water, electrical energy is converted into thermal energy, which increases the water's temperature. This transformation is a key concept in understanding how energy works in different scenarios.

Consider a roller coaster: at the top of a hill, it has maximum gravitational potential energy. As it descends, this potential energy is converted into kinetic energy, which is the energy of motion. When it climbs another hill, kinetic energy is converted back into potential energy. Throughout the ride, energy is constantly being transformed between these two forms, but the total energy remains the same, minus any losses due to friction and air resistance.

In chemical reactions, such as burning wood, chemical energy stored in the bonds of molecules is released as thermal energy and light. This is another example of energy transformation. Similarly, in electrical circuits, chemical energy in batteries is converted into electrical energy, which can then be transformed into light, heat, or mechanical energy depending on the device it powers.

Energy can also be transferred from one object to another. For instance, when you push a book across a table, kinetic energy is transferred from your hand to the book. However, some of this energy is also transformed into thermal energy due to friction between the book and the table.

Understanding these energy changes is crucial for analysing physical processes in everyday life and in scientific experiments. By recognising how energy is transferred and transformed, we can better understand the principles that govern the physical world.